2. A clean sheet approach to automotive design
direct-hydrogen fuel cell vehicles immi- says Taggart." The materials for an auto-
nently possible. mobile do not require aerospace spec, so
Hypercar produced the SUV manufacturing processes can be radically
crossover as its showcase model after simplified, and production costs drop
initial market research in the American accordingly. Cost was the primary driver
market. The average US driver typically in our design process."
demands plenty of r o o m inside the car,
good acceleration, with the ability to Safety first
carry a heavy payload, and the option Taggart and his team have brought
to handle mild oft-road conditions. breakthrough structural integrity and
Coupled with the company's own safety to their foundation platform by
product requirements of safety, fuel creating a passenger safety cell made of
efficiency, low emissions, and high vol- carbon fibre reinforced plastic (CFRP).
u m e production economics, Hypercar This passenger safety cell forms the main
has succeeded in coming up with a structure of the vehicle including sus-
product design, systems innovations pension and subframe interfaces, and
and manufacturing processes which houses the hydrogen tanks in order to
have truly brought the car into the 21st provide m a x i m u m protection and
century. Its technology could be ready greater safety for the tanks.
as early as 2005 for integration into Key to the affordability of the inte-
production models. grated design and production solution of
the vehicle is a proprietary processing
The clean sheet approach step which has the job of preparing the
How have they done it? David Taggart, equivalent of a tailored blank for sub-
senior vice president of product devel- sequent forming into a final component.
opment, was tasked with meeting this This innovation uses existing technolo-
strict set of product requirements. restricted to SUVs. The basic design gy, but in a very unique way. The process
Formerly of Lockheed Martin's aero- approach, and manufacturing goals, and allows production of 50 000 automotive
space engineering Skunk Works, where mentality of their 'foundation platform' safety cells per year in a combination of
he worked on the design and can be applied to any car, be it sportier, no more than three vehicle variants, and
production of a variety of aircraft and larger, smaller, more luxurious, or less so. uses aligned reinforcement to ensure a
challenging structural applications, Although he was originally schooled dramatic weight reduction. The process
Taggart brought his unique interpreta- as an undergraduate in metallurgical is highly repeatable, tailorable, moni-
tion of the Skunk Works development engineering, Taggart was, nevertheless, torable and controllable, and allows the
process with h i m to Hypercar. He kept a inspired by the design flexibility and use of either thermosets or thermo-
small expert team of development engi- outstanding properties of composites. He plastics, and either modified stamping or
neers in an intimate working environ- then went on to a graduate degree and a resin infusion processes in the final
m e n t where he encouraged a discipline professional career in advanced materi- processing step to complete the overall
of constant dialogue and rigorous deci- als, structural design, and programme production process.
sion making as a means of achieving management prior to coming to The safety cell has been analyzed
systems breakthroughs without com- Hypercar. There was, therefore, no doubt using automotive industry standard
promising the product requirements. for him that the resulting design needed tools and shown to withstand a
The clean sheet approach they to be composites intensive, including, of 56 k m / h r (35 mph) head on collision
applied allowed t h e m to arrive at inno- course, the compressed hydrogen tanks. with a stationary object and still remain
vative approaches to meeting the prod- Taggart then applied the aerospace undamaged. This far exceeds regular
uct requirements, while radically simpli- design mentality, and brought aerospace safety standards, but the team built this
fying the design and processes to manufacturing processes into the equa- level of safety into the design, not only
manage production costs. This has tion to broaden the team's design free- for structural reasons, but also for the
resulted in a platform design and pro- d o m and deliver the required repeatabili- benefit of repair and reuse. In factoring
duction solution that meets the product ty and performance. durability and re-use into the vehicle,
requirements, and can be affordably pro- "Air vehicle engineering typically has the design compensates for the cost of
duced at attractive volumes. Yet the to deal with intense loads and system repairing CFRP structures by forcing
design they have engineered is not complexity. That is not the case here," energy absorption to occur in the front
Se p t e m b e r 2 0 0 1 R£11W~V~Dplaslics 55
3. A clean sheet approach to automotive design
of the c o m p o n e n t s are designed to be
reused in other product forms, and
the vehicle's digital 'nervous system',
incorporating the latest software and
electronics, can be remotely upgraded
diagnosed and repaired, and to a large
degree, choreographs the dismantling
of the vehicle's c o m p o n e n t s at the end
of its useful life.
Economics
The design has not been without its hur-
dles though. Yet with their 'no compro-
mise' approach, the team has either
turned the problem into an overall prod-
uct advantage, such as making the struc-
ture so durable that it needs little repair,
or has simplified the problem so that it
does not present itself as one. It would,
for example, seem advantageous to make
the most of composites' properties to
of the vehicle. Energy distribution then sedans, which is outstanding for an SUV embed electronics into the material
takes place in the safety cell, thereby with 1.9 m 3 of cargo space. Working itself, and thus simplify the design fur-
allowing the vehicle to withstand within TWR's engineering facilities in ther. But, once again, repairing embed-
greater impacts with less damage. the UK, the Formula One specialist engi- ded wires, if needed, would be difficult,
Front and rear of the passenger safety neering consultancy, the Revolution's and it would add to the complexity and
cell are tailored crush zones. These are stylists have made the vehicle sleeker production cost of the structure, so the
designed to absorb increasing amounts than any other crossover SUV on the team has taken the decision to leave
of impact energy prior to damaging the market or even in the showroom. Yet on most of the electronics outside of the
passenger safety cell at higher speeds. the outside the vehicle appears no bigger structure.
The bumper is made of CFRP than a BMW X5 or a Lexus RX300. One of the unique outcomes of
designed to withstand impacts up to "The key to unlocking the weight and Hypercar's design approach is that it has
24 k m / h r (15 mph). cost reduction benefits of advanced com- brought the main structural frame inside
The next zone comprises a tubular posites is in the simplicity of the design the vehicle, instead of making it a part of
aluminium subframe, and numerous and overall integration of that design the outer surface.
suspension and system components. with an interdependent process solu- Taggart maintains that separating the
Aluminium was chosen because of its tion," says Taggart. "By working very structure from the skin was desirable for
ability to easily manage a variety of hard to tailor the structural design, and a number of reasons, one being that it
structural hard points and geometric by developing the production processes is possible to change the outer skin of
complexity at low cost, while providing ideally suited to producing the parts, we the vehicle as styles change over the
a low risk and repeatable energy absorp- have greatly simplified the overall tool- years. More importantly, the structural
tion solution. ing, production and assembly approach. components could be tailored to do
Finally, covering the entire passenger The design is now so simple that the the job required of the structure, in as
safety cell, and front and rear crush components of the safety cell fit together low cost a manner as possible. Coupled,
zones, is a thermoplastic and reusable with m i n i m u m effort, m u c h like a Revell in addition, with all the other upgrade-
skin to enable tailored vehicle style, in- toy model kit." able features of the vehicle, the design
mould colour, and dent resistance. Durability has been built into the allows an individual to considerably
Combined with the smooth underbelly design from the beginning. This is upgrade a vehicle without having to buy
of the safety cell, this combination another of the advantages of compos- a new car.
affords a reduction in drag coefficient ites, which do not rust, or degrade Hypercar's target production volume
and gain in fuel efficiency. The easily, and in this case, do not go is 50 000 units per year, which repre-
Revolution has a drag coefficient of 0.26, through an expensive and environmen- sents an important threshold level for
making it more aerodynamic than most tally detrimental spray paint job. Most the original equipment manufacturers
56 P.EIl~lCEDplastics September 2001
4. A clean sheet approach to automotive design
(OEMs). The c o m p a n y forecasts that its "Making something simple is a upgradeability is the key to niche mar-
average production spec will be higher in complex process," says Taggart, "whereas kets and will give the manufacturer
materials costs, but considerably lower in it is very simple to make something which takes up its design concepts and
assembly and production overhead costs. complex." systems innovations the competitive
Its clean sheet approach and whole edge over the manufacture of conven-
system vehicle understanding has tional steel vehicles.
emphasized the need to eliminate ineffi-
Low retooling costs would Hypercar's product development
ciencies and minimize waste throughout allow for highly tailorable approach and technical innovations are
the entire manufacturing process. The a game changer for sure, and it will be
design as a result is also extremely effi-
production runs. inspiring for composite material produc-
cient on accessory loads and perform- ers and manufacturers around the world
ance, especially for a car that can get With such a simple vehicle design to track what might be the first 'volume
0-96 k m / h r (60 mph) in 8.3 seconds, and correspondingly affordable manu- production carbon reinforced solution'
with four wheel drive capability and facturing costs, it would, therefore, not inroad into the automotive world. •
variable attitude control and ground be a big investment for Hypercar to
clearance. It would be difficult to com- retool for a new design. Low retooling
pare these economics to other composite costs would allow for highly tailorable
vehicles as they tend to deal only in production runs, something which only Hypercar Ira:, I I 0 Midland Avenue, Suite
smaller volumes, and avoid high manu- Toyota is really striving to do with 202, Basalt, C O 81621, USA; tel: +1-
facturing costs by making composites steel cars, and which to date has eluded 970-927-4556; fax: +1-970-927-4593;
only a part of the structural solution and the conventional car manufacturer. website: w w w . ~ c o m .
less a part of the chassis system. Hyper-car forecasts that tailorability and
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